Modern vehicle assembly plants often employ skillet conveyors to move vehicles along an assembly line. Assembly workers are stationed along the assembly line and perform the various operations involved in assembly of the vehicles.
A skillet conveyor includes a large platform, known as a skillet, which is about the size of the vehicle that is to be conveyed. A large number of these skillets are placed end-to-end, single file, engaging with one another, and ride along a track that is recessed into the floor of the assembly plant.
The continuous row of individual skillets is driven along the track by skillet drives that are provided at intervals along the track as the track winds its way though the assembly plant. Each skillet drive includes a motor unit that rotates a urethane drive wheel that is pressed against the side of the skillet. Rotation of the urethane drive wheel will thus propel the skillet along the track. Accordingly, the drive wheels need to be pressed against the sides of the platform with sufficient force that the rotation of the drive wheels will reliably move the heavy skillet along the track.
The skillet drive units typically include mounting of the motor and urethane drive wheel on a cantilever support or other moveable mounting arrangement to permit the motor unit and drive wheel to be adjustably moved toward and away from the skillet in order to either increase or decrease the pressure of the drive wheel against the side of the skillet. The magnitude of the pressure is determined by a spring mechanism such as a beveled washer spring pack that resiliently urges the cantilever support in the direction toward the skillet.
During the installation and maintenance of the skillet conveyor system in the assembly plant, the spring pack is adjusted to the requisite force by measuring the compression of the spring pack. For example, if the spring pack has a spring compression rate of 2500 pounds per inch of compression, and it is determined that a wheel load of 1250 pounds is desired for conveying the weight of the skillet and the vehicle body carried by the skillet, then the drive unit will be adjusted so that the drive wheel is pressed against the skillet with 0.5 inch of compression of the spring pack.
The typical vehicle assembly plant will have dozens of these skillet drives that need to be adjusted from time to time and It would be desirable to provide a new and improved method for adjusting the force load of the drive wheel against the skillet.